1. Field of the Invention
The invention relates to a vehicle light for illumination, such as a headlight, indication light, tail light, fog light, etc. In particular, the invention relates to a vehicle light suitable for a vehicle headlight in which a basic projector type headlight is provided with additional ellipse group reflecting portions and additional parabolic group reflecting portions to effectively utilize light which has not been used by the conventional projector type headlight. This configuration can provide a high luminous flux capture rate (or light utilization efficiency) for a vehicle headlight which can result in a high level of luminance.
2. Description of the Related Art
FIG. 1 shows an exemplary configuration of a conventional projector type headlight 90 with additional reflectors 81 to 84 provided in order to increase the light amount emitted therefrom (for example, see the headlight disclosed in both Japanese Patent Laid-Open Publication No. 2003-151319 and family patent member U.S. application No. 2003/008277, the disclosures of which are hereby incorporated in their entirety by reference). The projector type headlight 90 has a main reflector 92 that comprises an ellipse group reflecting portion such as a revolved ellipsoid. The main reflector 92 has a first focus f1 and a second focus f2. A light source 91 such as a metal halide discharge light is provided approximately at the position of the first focus f1. The main reflector 92 is arranged such that the second focus f2 is located in front of the first focus f1 on the illumination axis X.
A projection lens 93 is arranged in front of the second focus f2 of the main reflector 92 on the illumination axis X and has a focus located approximately at the position of the second focus f2. A movable shielding plate 94 is arranged in the vicinity of the second focus f2 such that the lower half of the reflected light from the main reflector 92 can be appropriately shielded. The shielding plate 94 can move between the low-beam position and the high-beam position. When the shielding plate 94 is at the low-beam position, upward light can be shielded thereby to obtain a low-beam distribution. When the shielding plate 94 is at the high-beam position, upward light is not shielded in order to obtain a high-beam distribution.
In addition to the basic configuration of the projector type headlight 90 described above, the additional reflectors 81 to 84 are provided, which will be described later, to increase the light amount. In this description related to the conventional art, the right and left directions are defined based on the illumination direction seen from the light source 91 side.
One of the additional reflectors, or a first right additional reflector 81, is arranged at the position between the main reflector 92 and the projection lens 93 where there is no obstacle such as a shielding plate 94 or the like, and at the upper portion where only direct light from the light source 91 reaches. The reflector 81 has a first focus f1 and a second focus f3R. The reflector 81 is arranged such that the first focus f1 is positioned approximately at the light source 91 and the second focus f3R is positioned leftward and below the illumination axis X.
A second left additional reflector 82 is provided at the position near the lower left portion of the projector type headlight 90. The reflector 82 has a focus positioned approximately at the second focus f3R of the reflector 81 with its reflection direction being generally parallel to the illumination axis X.
In addition, a first left additional reflector 83 and a second right reflector 84 are provided symmetrically with respect to the first right additional reflector 81 and the second left additional reflector 82.
Incidentally, in the conventional example, auxiliary shielding plates are provided between the first right additional reflector 81 and the second left additional reflector 82 and between the first left additional reflector 83 and the second right additional reflector 84, respectively. They are opened and closed in cooperation with the movable shielding plate 94.
When the movable shielding plate 94 takes the high-beam position, or in the high-beam distribution state in the conventional headlight 90, the light amount can be increased by the amount captured by the first right additional reflector 81 and the first left additional reflector 83.
However, the vehicle light with the conventional configuration has the following problems. First, the first right and left additional reflectors 81 and 83 can capture only a part of light which is not captured by the main reflector, namely they reflect only a part of the light which is not effectively used. This is because the positional interference should be avoided when arranging the second reflectors 82 and 84. Thus, the light amount increased by the afore-mentioned configuration of the vehicle light is not sufficient with respect to the complexity of the configuration of the vehicle headlight. Thus, the cost performance is not satisfactory.
Another problem is that the reflecting surfaces of the first right and left additional reflectors 81 and 83 are inevitably directed toward the light source because the reflectors 81 and 83 must directly capture the light from the light source. Namely, when the vehicle light is seen from the front, the rear sides of the reflectors 81 and 83 are directly observed. These areas are not lit when the light source is turned on, resulting in a strange or uneven light that might be bothersome for viewers. In addition, the lit portion corresponding to the projection lens is separated from those corresponding to the second right and left additional reflectors. This also results in a possibly strange or uneven light that may not meet aesthetic desires.